It is often desirable and many times necessary to fix the axial clearances in rotating machines during the assembly steps rather than during the manufacturing steps. This relaxes the tolerance control required during the manufacturing of the various components. The axial clearances between a high speed rotating part and a stationary housing for example may be extremely tight. Attempting to manufacture the various components with precise tolerances result in high manufacturing costs due to tolerance build-up. Alternatively, manufacturing the components with relaxed tolerances but having a means for precisely adjusting the clearances during the assembly step usually is more cost effective.
Various types of positioning nuts have been used to provide axial adjustment during the assembly steps. Usually an adjusting mechanism moves one component axially along a shaft to provide the proper clearance. Then the adjusting means and component are locked onto the shaft to keep the component in the correct clearance position.
One known lockable nut which could be used as a positioning means is disclosed in U.S. Pat. No. 4,557,652. This patent discloses a nut having two annular parts axially connected by resilient plugs. Locking occurs by tightening a screw in one annular part which abuts against and axially skews the other annular part on the nut thread.
The known precision adjusting nuts tend to be complex and expensive because of the number of parts, the different materials, and the steps required to produce and install the nut. Additionally the known adjusting nuts are not suitable for certain situations. Some adjusting and locking means must be accessible and operatable from a common position. Also the adjusting mechanism must be reliably and precisely reuseable.
It is believed that the simple and inexpensive lockable adjusting nut according to the present invention resolves these problems.